Kim Jong Un wanted to assassinate his half-brother in the most “gruesome” and public way possible earlier this year to “horrify the rest of the world” and instill fear among his doubters, according to a Monday report.

The daring assassination of Kim Jong Nam in February undertaken by two prostitutes in Malaysia’s Kuala Lumpur airport has mostly been shrouded in mystery, with few reports from South Korean media speculating why the estranged half-brother of the North Korean despot was killed.

A South Korean spy agency initially said the death was part of the leader’s five-year plot. A Korea University professor investigating the assassination — and who previously led a research arm with South Korea’s intelligence agency — told GQ on Monday it was all “part of a master plan.”